This invention relates generally to impingement coolers, and, more particularly, to impingement coolers capable of low thermal resistance and large heat flux heat removal.
A variety of devices of interest require removal of a large heat fluxes. For example, although other examples are also possible, high-power laser diodes could require heat removal at a heat flux greater than 0.5 kW/cm2 with low thermal resistance. In addition, having a spatially varying resistance would be very beneficial. Conventional heat removal technologies limit laser diode scaling to about 200 w/bar-cm.
While the above detailed example presents the need for improved methods for cooling (heat removal) in laser diodes, other solid-state devices (such as, but not limited to, microwave/millimeter wave monolithic integrated circuits-MIMICs, computer CPUs, concentrator photovoltaic cells, etc.) produce a large waste heat output that also has to be removed.
Several approaches have been used for removing the heat from solid-state devices. In one approach, confined-flow heat exchangers are built into or located adjacent to the heat-producing surfaces of the solid-state device. While such confined-flow heat exchangers are operable, they cannot remove heat at the high rates required for high-power devices that produce very large heat fluxes. They are also limited in their ability to compensate devices that generate waste heat that is spatially dependent.
Jet impingement coolers have also been used. In this approach, one or more jets of a coolant, typically a liquid, are directed at the surface to be cooled. This approach is also operable but has shortcomings. The existing designs have a limited ability to remove large amounts of heat, unless the flow rate of coolant is so high as to be impractical for many situations. Additionally, there are temperature gradients across the surface being cooled, resulting in undesirable transverse thermally induced strain in the solid-state device or non-optimum performance of the solid-state device. Jet impingement coolers that operate at low pressure are also much thicker than is practical for laser diode arrays and stacks. In addition, none of these devices have a thermal resistance that can compensate for spatially varying waste heat generation.
There is a need to provide improved methods of heat removal for devices requiring removal of a large amounts of heat, while simultaneously providing a low thermal resistance, a low heat source temperature and with dimensions that are narrow such that it can accommodate compact geometries.
In order to produce high brightness laser diode systems, laser diodes in conjunction with their heat removal component (cooler) can be stacked. The thickness of present heat does not allow for high brightness laser diode systems configured by stacking laser diode subsystems. There is a need for a heat removal component design that allows for thinner heat removal components.